LIFE 103 1st Edition Lecture 8Outline of Last Lecture I. MossesI. Anatomy II. SequenceIII. Ecology II. Ferns and other seedless plants I. Anatomy II. Other derived traitsIII. Diversity Outline of Current Lecture II. A Summary of Life III. Key Features of Seed Plant EvolutionI. Increased dominance of the sporophyte II. Appearance of air-borne pollen to bring gametes together III. Seeds IV. Seeds V. Gymnosperm AnatomyI. Female II. Male III. FertilizationIV. Embryo i. Fig. 30.6VI. Diversity Current Lecture: Seed plants: Gymnosperms A Summary of LifeI. Reproduce (ultimate goal)I. Eat II. Grow III. Avoid dyingII. There are tradeoffs; you can’t be good at everything III. Natural selection favors organisms that are best at living under current conditions IV. Fig. 29.7: Phylogeny tree of plant ancestors These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Key Features of Seed Plant EvolutionI. Increased dominance of the sporophyteI. Gametophyte stage is microscopic II. Appearance of air-borne pollen to bring gametes togetherI. Eliminates need for swimming through water III. Seeds SeedsI. Resistant to harsh conditions II. Can be dormant until the environment is favorable III. Allows for wide dispersal IV. Nourish sporophyte during germination and early growth Compare and Contrast: Embryos Fern: I. Egg and sperm come together to form a zygote (in gametophyte)II. Creates multicellular embryo (on gametophyte)III. Sporophyte (independent) Seed plant: I. Egg and Sperm come together to form a zygote (in gametophyte) II. Creates multicellular embryo (on gametophyte) III. Sporophyte (independent) Gymnosperms (“naked” + “seeds”) Gymnosperm Female AnatomyI. Megasporangium: diploid tissue where haploid megaspore is formed (meiosis)II. Megaspore: haploid cell that grows into the female gametophyte, including the egg nucleus III. Ovule: megasporangium plus megaspore, wrapped in sporophyte’s protective cover (“integument”) Gymnosperm Male Anatomy I. Microsporangium: diploid tissue where haploid microspores are formed (meiosis) II. Microspores: develop into male gametophyte III. Pollen: contains the male gametophyte within the tough pollen wall (mirrors the ovule of the female)Gymnosperm FertilizationI. Pollen released into the air, spreads for miles II. Pollen grain reaches ovule and germinatesIII. Pollen tube grows, digesting through megasporangium (container for the megaspore) IV. Pollen tube reaches egg nucleus, discharges sperm nucleus into egg nucleus of female gametophyte Gymnosperm EmbryoI. Embryo is sporophyte that develops, then pauses (diploid) II. Embryo itself is diploidIII. Surrounded by female gametophyte tissue that are food reserves IV. Fig. 30.3: Unfertilized ovule into fertilized ovule, gymnosperm seed (new sporophyte) I. Seed coat (derived from integument)II. Food supply (female gametophyte tissue) (n) III. Embryo (2n) (new sporophyte) IV. Example: pine nut V. Fig. 30.6: IMPORTANT FIGUREI. Showcases the process of fertilization through meiosis II. Clicker questions: What is the Ploidy of the seed embryo? Diploid III. Where are pollen grains produced? Microsporangia IV. Male and female classification goes down to gametes: egg and spermDiversity: Gymnosperm Phyla I. Coniferophyta (>600 species)I. Fir, pine, larch, juniper, sequoia II. Cycadophyta (130 species)I. Palm-like leaves with a large coneIII. Gnetophyta (76 species)I. Oddballs IV. Ginkos (1 species)I. Example of dioecious (separate male and female plants)II. Female trees produce fleshy seeds that rot and stink! V. Examples I. Douglas Fir, #1 source of wood in North AmericaII. Bristlecone pine, among the oldest living organismsIII. Giant Sequoia, among the largest and most troublesome organisms IV. Common juniper, berries used in production of gin V. Cycas revolute, leaves like palmsVI. Ginkgo biloba, stinky when seeds rot, have fleshy seeds VII.